Answer:
As the plane moves toward the listener, the apparent frequency of the plane would be [tex]4250\; {\rm Hz}[/tex] ([tex]2250\; {\rm Hz}[/tex] higher than the frequency at the source.)
As the plane moves away from the listener, the apparent frequency of the plane would be approximately [tex]1308\; {\rm Hz}[/tex] (approximately [tex]692\; {\rm Hz}[/tex] lower than the frequency at the source.)
Assumption: the speed of sound in the air is [tex]340\; {\rm m\cdot s^{-1}}[/tex].
Explanation:
Crests of this sound wave travel toward the listener at a constant [tex]v = 340\; {\rm m\cdot s^{-1}}[/tex]. Since there is a pause of [tex]t = 1 / f = (1/2000)\; {\rm s}[/tex] between every two consecutive crests of this sound wave, the distance between each pair of consecutive crests would be:
[tex]\begin{aligned}\lambda &= \frac{v}{f} \\ &= \frac{340\; {\rm m \cdot s^{-1}}}{2000\; {\rm s^{-1}}} \\ &= 0.17\; {\rm m} \end{aligned}[/tex].
Hence, if the aircraft wasn't moving, the first crest would have a head start of [tex]\lambda = 0.17\; {\rm m}[/tex] relative to the second one. This head start would ensure that the first crest arrive [tex]t = \lambda / v = 0.17\; {\rm m} / (340\; {\rm m \cdot s^{-1}}) = (1/2000)\; {\rm s}[/tex] earlier than the second crest.
However, at a speed of [tex]v_{\text{s}} = 180\; {\rm m\cdot s^{-1}}[/tex], the aircraft would have travelled an additional [tex]v_\text{s}\, t = 180\; {\rm m\cdot s^{-1}} \times (1/2000)\; {\rm s} = 0.09\; {\rm m}[/tex] within that [tex]t = (1 / 2000)\; {\rm s}[/tex].
If the aircraft was travelling towards the listener, the head start of the first crest over the next one would be reduced to [tex]\lambda - v_\text{s}\, t =[/tex][tex]0.17\; {\rm m} - 0.09\; {\rm m} = 0.08\; {\rm m}[/tex]. The first crest would arrive earlier than the second one by [tex](\lambda - v_{\text{s}}\, t) / (v) = (0.08\; {\rm m}) / (340\; {\rm m\cdot s^{-1}}) \approx 0.000235\; {\rm s}[/tex].In contrast, if the aircraft was travelling away from the listener, the head start of the first crest over the next one would be increased to [tex]\lambda + v_\text{s}\, t = 0.17\; {\rm m} + 0.09\; {\rm m} = 0.26\; {\rm m}[/tex]. The first crest would arrive earlier than the second one by [tex](\lambda + v_{\text{s}}\, t) / (v) = (0.26\; {\rm m}) / (340\; {\rm m\cdot s^{-1}}) \approx 0.000765\; {\rm s}[/tex].In other words, if the aircraft was moving towards the listener, the period of the sound would appear to the listener to be approximately [tex]0.000235\; {\rm s}[/tex]. in contrast, if the aircraft was moving away from the listener, the period of the sound would appear to the listener as approximately [tex]0.000765\; {\rm s}[/tex].
Therefore:
When the aircraft moves toward the listener, the listener would hear a frequency of [tex]f = 1 / t \approx 1 / 0.000235\; {\rm s} = 4250\; {\rm Hz}[/tex].When the aircraft moves away from the listener, the listener would hear a frequency of approximately [tex]f = 1 / t \approx 1 / 0.000765\; {\rm s} \approx 1307\; {\rm Hz}[/tex].Air at 68°F and 1 atm flows inside a pipe at a mass flow rate of 0.13 lb/s. What is the minimum diameter of the pipe if the flow is to be laminar? Take p = 2.34E-3 slug/f3 and 4 = 3.76E-7 lb-s/12 The minimum diameter of the pipe if the flow is to be laminar is Eft
The minimum diameter of the pipe for laminar flow is: 0.019 ft or 0.23 inches.
The minimum diameter of the pipe for laminar flow can be calculated using the Reynolds number, which is given by:
Re = (ρVD)/μ,
where ρ is the density of the fluid,
V is the velocity of the fluid,
D is the diameter of the pipe, and
μ is the dynamic viscosity of the fluid.
For laminar flow, the Reynolds number should be less than or equal to 2300.
Using the given values, the density of air at 68°F and 1 atm can be calculated as,
ρ = 2.34E-3 slug/ft^3,
and the mass flow rate can be converted to velocity using the formula,
V = (mdot/ρA),
where A is the cross-sectional area of the pipe.
Rearranging this formula to solve for A and substituting the given values yields,
A = (πD^2)/4 = mdot/(ρV) = 0.41 ft^2.
Substituting the given values into the Reynolds number formula and solving for D, we get:
Re = (ρVD)/μ
2300 = (ρVD)/μ
D = (2300μ)/(ρV)
Substituting the given values for μ, ρ, and V and solving for D, we get:
D = (2300 x 3.76E-7)/(2.34E-3 x 0.13/0.41) = 0.019 ft
To know more about "Laminar flow" refer here:
https://brainly.com/question/23008935#
#SPJ11
true/false. the angle between the incident ray and the reflected ray in a convex mirror is 20o. we can assure that, at that point the normal and the incident ray had a 10o angle.
False. The angle between the incident ray and the reflected ray in a convex mirror is not necessarily 20º. We cannot assure that at that point, the normal and the incident ray had a 10º angle.
In a convex mirror, the angle of incidence and the angle of reflection are measured with respect to the normal at the point of incidence. According to the law of reflection, the angle of incidence is equal to the angle of reflection. Therefore, if the angle between the incident ray and the reflected ray is 20º, it means that the sum of the angles of incidence and reflection is 20º. However, without more information, we cannot determine the exact angles of incidence and reflection in this scenario. It is not necessarily true that the normal and the incident ray had a 10º angle.
To know more about a convex mirror, click here;
https://brainly.com/question/3627454
#SPJ11
the current lags the emf by 30 ∘∘ in a series rlcrlc circuit with e0=25ve0=25v and r=50ωr=50ω. part a part complete what is the peak current through the circuit?
The peak current in the series RLC circuit, where the current lags the EMF by 30°, is approximately 0.5 A.
In a series RLC circuit with a given EMF, resistance, and phase angle between the current and the EMF, the peak current can be calculated using the impedance of the circuit. The impedance (Z) is the vector sum of the resistance (R), inductive reactance (XL), and capacitive reactance (XC). In this case, the resistance (R) is given as 50 Ω.
Since the current lags the EMF by 30°, we can use the cosine of the phase angle (cos(30°)) to determine the ratio of the resistance to the impedance:
cos(30°) = R/Z
From this, we can solve for Z:
Z = R / cos(30°) = 50 Ω / cos(30°) ≈ 57.74 Ω
Now, we can use Ohm's Law to find the peak current (I_peak) in the circuit:
I_peak = E0 / Z = 25 V / 57.74 Ω ≈ 0.433 A
However, considering the possible rounding errors and the fact that the question requires the answer in one decimal place, the peak current can be approximated as 0.5 A.
To know more about the RLC circuit, click here;
https://brainly.com/question/29898671
#SPJ11
(a) obtain the wavelength in vacuum for blue light, whose frequency is 6.481 1014 hz. express your answer in nanometers (1 nm = 10−9 m).
Blue light having a frequency of 6.481 x 10¹⁴ Hz has a wavelength of around 462.2 nm in a vacuum.
The wavelength of blue light can be determined using the equation λ = c/ν, where λ is the wavelength, c is the speed of light in a vacuum, and ν is the frequency of the light.
Plugging in the given frequency of 6.481 x 10¹⁴ Hz and the speed of light, which is approximately 3 x 10⁸ m/s, we get:
λ = (3 x 10⁸ m/s)/(6.481 x 10¹⁴ Hz)
λ ≈ 462.5 nm
Therefore, the wavelength of blue light with a frequency of 6.481 x 10¹⁴ Hz is approximately 462.5 nm.
To know more about the wavelength refer here :
https://brainly.com/question/4112024#
#SPJ11
fitb. ______ is any unconsolidated or weakly consolidated material at the earth's surface, regardless of particle size or composition.
"Soil is any unconsolidated or weakly consolidated material at the earth's surface, regardless of particle size or composition."
Soil is a mixture of minerals, organic matter, air, water, and living organisms. consolidated material at the earth's surface, regardless of particle size or composition. It forms through the processes of weathering and the interaction of various factors such as climate, topography, parent material, organisms, and time. Soil plays a crucial role in supporting plant growth, providing nutrients, regulating water flow, filtering pollutants, and serving as a habitat for many organisms. It varies in composition and characteristics across different regions and has significant importance in agriculture, ecology, and land management.
Learn more about Soil is any unconsolidated or weakly here:
https://brainly.com/question/32282596
#SPJ11
an excited nucleus emits a gamma-ray photon with an energy of 2.70 mev . part a what is the photon’s energy in joules? express your answer in joules.What is the photon's frequency? Express your answer in hertz.
The photon's energy in joules is 4.32 x [tex]10^{-13[/tex] J, and its frequency is 6.53 x [tex]10^{20[/tex] Hz.
To convert the energy of the gamma-ray photon from MeV to joules, use the conversion factor:
1 MeV = 1.602 x [tex]10^{-13[/tex] J.
Multiply the given energy by this factor:
2.70 MeV x 1.602 x [tex]10^{-13[/tex] J/MeV = 4.32 x [tex]10^{-13[/tex] J.
To find the frequency, use the Planck's equation:
E = hν,
where
E is energy,
h is Planck's constant (6.63 x [tex]10^{-34[/tex] J s), and
ν is the frequency.
Rearrange the equation to solve for frequency:
ν = E/h.
Substitute the energy in joules: ν = (4.32 x [tex]10^{-13[/tex] J) / (6.63 x [tex]10^{-34[/tex] J s) = 6.53 x [tex]10^{20[/tex] Hz.
For more such questions on frequency, click on:
https://brainly.com/question/254161
#SPJ11
The frequency of the gamma-ray photon is 6.53 x [tex]10^{20[/tex] Hz.
The energy of a gamma-ray photon can be converted from electronvolts (eV) to joules (J) using the conversion factor:
1 eV = 1.602 x [tex]10^{-19[/tex]J
Therefore, the energy of the gamma-ray photon with an energy of 2.70 MeV (mega-electronvolts) can be calculated as follows:
E = 2.70 MeV x 1,000,000 eV/1 MeV x 1.602 x [tex]10^{-19[/tex] J/eV
E = 4.33 x [tex]10^{-13[/tex] J
So the energy of the gamma-ray photon is 4.33 x [tex]10^{-13[/tex] J.
The frequency of the gamma-ray photon can be calculated using the equation:
E = hf
where E is the energy of the photon, h is Planck's constant (6.626 x 10^-34 J s), and f is the frequency of the photon. Rearranging this equation to solve for f, we get:
f = E/h
Substituting the value of E we just calculated and the value of h, we get:
f = (4.33 x[tex]10^{-13[/tex] J)/(6.626 x [tex]10^{-34[/tex] J s)
f = 6.53 x [tex]10^{20[/tex] Hz
Learn more about Planck's constant here:
https://brainly.com/question/30763530
#SPJ11
Explain how the shape of planetary orbits affects their orbital velocity. Include the proper law of planetary motion as part of your answer.
Answer:
The shape of planetary orbits affects their orbital velocity because the speed of a planet in its orbit is not constant. According to Kepler's laws of planetary motion, the planets move in elliptical orbits with the sun at one of the two foci of the ellipse.
Kepler's second law, also known as the law of equal areas, states that a line that connects a planet to the sun sweeps out equal areas in equal times as the planet travels around the sun. This means that a planet's speed varies throughout its orbit.
When a planet is closer to the sun (at perihelion), it travels faster as it is subject to a stronger gravitational pull. Conversely, when a planet is farther from the sun (at aphelion), it travels slower due to the weaker gravitational pull.
Therefore, the shape of a planet's orbit determines its distance from the sun and, consequently, the strength of the gravitational force acting on it, which in turn affects its orbital velocity.
The decay n - p + e- cannot happen because something is clearly not conserved. What is not conserved, among what needs to be conserved? O momentum O mass lepton number O energy O charge O angular momentum baryon number
The decay n - p + e- cannot happen then the conservation of energy, momentum, baryon number, and angular momentum would be violated. And the conservation of mass and lepton number would not be violated in this decay process.
The decay n - p + e- cannot happen because the conservation of several quantities is violated. Specifically, the conservation of baryon number and electric charge is violated, as the neutron (n) has a baryon number of 1 and no electric charge, while the proton (p) has a baryon number of 1 and a positive electric charge, and the electron (e-) has a baryon number of 0 and a negative electric charge. Additionally, the conservation of energy, momentum, and angular momentum would also be violated in this decay process. However, the conservation of mass and lepton number would not be violated in this decay process.
To learn more about decay visit: https://brainly.com/question/11117468
#SPJ11
two stars have the same inherent brightness (absolute magnitude). star a appears 1/16 as bright as star b. star a is 4 light years away. star b must be
Star b must be 2 light years away. The apparent brightness of a star decreases with the square of the distance. Since star a appears 1/16 as bright as star b, star b must be √16 = 4 times closer, which is 2 light years away.
The apparent brightness of a star is determined by its intrinsic brightness, also known as its absolute magnitude, and its distance from the observer. In this scenario, star a and star b have the same absolute magnitude, indicating that they have the same inherent brightness. However, star a appears 1/16 as bright as star b. Since apparent brightness is inversely proportional to the square of the distance, we can deduce that star b must be 1/4 times the distance of star a to maintain the same apparent brightness. Given that star a is 4 light years away, star b must be 2 light years away. This ensures that the apparent brightness of star b is 1/16 of star a, as observed.
Learn more about absolute magnitude here:
https://brainly.com/question/30691550
#SPJ11
A traveling electromagnetic wave in a vacuum has an electric field amplitude of 91.5 V/m . Calculate the intensity of this wave. Then, determine the amount of energy that flows through area of 0.0229 m2 over an interval of 17.1 s , assuming that the area is perpendicular to the direction of wave propagation.
S= ___W/m2
U= ___ J
Therefore, the amount of energy that flows through the given area over the given time interval is 1.31 x 105 J.
To calculate the intensity of the electromagnetic wave, we can use the formula:
I = (1/2) * ε0 * c * E0^2
where I is the intensity, 0 is the permittivity of free space (8.85 x 10-12 F/m), c is the speed of light in a vacuum (3 x 108 m/s), and E0 is the electric field amplitude.
Substituting the given values, we get:
I = (1/2) * (8.85 x 10-12 F/m) * (3 x 10-8 m/s) * (91.5 V/m)
I = 3.93 x 10^-6 W/m^2
Therefore, the intensity of the electromagnetic wave is 3.93 x 106 W/m2.
To determine the amount of energy that flows through an area of 0.0229 m2 over an interval of 17.1 s, we can use the formula:
U = I * A * t
where U is the energy, A is the area, and t is the time interval.
Substituting the given values, we get:
U = (3.93 x 10^-6 W/m^2) * (0.0229 m2) * (17.1 s)
U = 1.31 x 10^-5 J
Therefore, the amount of energy that flows through the given area over the given time interval is 1.31 x 105 J.
To know more about electromagnetic wave visit:-
https://brainly.com/question/3101711
#SPJ11
to a fish in an aquarium, the 4.50-mmmm-thick walls appear to be only 3.20 mmmm thick. What is the index of refraction of the walls?
The index of refraction of the walls is approximately 1.87.
The index of refraction is a measure of how much a material can bend or refract light. It is defined as the ratio of the speed of light in a vacuum to the speed of light in the material.
In this case, the fish is observing the thickness of the walls through water, which has a refractive index of approximately 1.33. When light travels from one medium to another with a different refractive index, it can change direction or bend. This bending is what causes the apparent change in thickness of the walls as observed by the fish.
To find the index of refraction of the walls, we can use the following formula:
n = (d_actual / d_apparent) x n_medium
where n is the index of refraction of the walls, d_actual is the actual thickness of the walls, d_apparent is the thickness of the walls as observed by the fish, and n_medium is the refractive index of the medium (in this case, water).
Substituting the given values, we get:
n = (4.50 mm / 3.20 mm) x 1.33 = 1.87
So the index of refraction of the walls is approximately 1.87.
This means that light travels slower through the walls than it does through water, and that the walls can bend or refract light more than water can. This property can be useful in optics and engineering, where materials with specific refractive indices are used to control the behavior of light in various applications, such as lenses and prisms.
To know more about index of refraction, refer to the link below:
https://brainly.com/question/29081640#
#SPJ11
if a very distant galaxy looks blue overall to astronomers, from this they can conclude that
If a very distant galaxy appears blue overall to astronomers, they can conclude that the galaxy is likely undergoing active star formation because blue light is predominantly emitted by young, hot, and massive stars.
If astronomers observe a very distant galaxy and find that it appears blue overall, they can infer that the galaxy is likely undergoing active star formation. Blue light is predominantly emitted by young, hot, and massive stars. The presence of blue light indicates the presence of recently formed stars, as these stars have shorter lifespans compared to older stars. The blue light is a result of the high surface temperatures of these young stars. Therefore, the overall blue color suggests that the galaxy is actively producing new stars, possibly due to favorable conditions such as an abundance of gas and dust, triggering ongoing star formation processes within the galaxy.
Learn more about astronomers here:
https://brainly.com/question/1764951
#SPJ11
determine the velocity of the block at the instant θ=60° if link ab is rotating at 4rad/s
In order to determine the velocity of the block at the instant θ=60°, we need to use the equation: v = rω. Where v is the velocity of the block, r is the distance between the block and the center of rotation, and ω is the angular velocity of link ab.
At the instant θ=60°, the distance between the block and the center of rotation is the length of link bc, which is given by: bc = 0.3m.
The angular velocity of link ab is given as: ω = 4rad/s.
Therefore, the velocity of the block at the instant θ=60° is: v = bc x ω = 0.3m x 4rad/s = 1.2m/s.
So, the velocity of the block at the instant θ=60° is 1.2m/s.
Read more about the Velocity of block.
https://brainly.com/question/31623770
#SPJ11
Consider an electrical load operates at 120 V rms. The load absorbs an average power of 9KW at a power factor of 0.7 (lagging). (a) Calculate the impedance of the load. (b) Calculate the complex power of the load. (c) Calculate the value of capacitance required to improve the power factor from 0.7 (lagging) to 0.95
(a) Calculate the impedance of the load using the given formulas and values.
(b) Calculate the complex power of the load using the given formulas and values.
(c) Calculate the value of capacitance required to improve the power factor using the given formulas and values.
(a) The impedance of the load can be calculated using the formula:
Impedance = Voltage / Current
Since we're given the average power, we can find the current using the formula:
Power = Voltage x Current x Power factor
Current = Power / (Voltage x Power factor)
Impedance = Voltage / Current
(b) The complex power of the load can be calculated using the formula:
Complex Power = Apparent Power x Power factor
Apparent Power = Voltage x Current
Complex Power = Voltage x Current x Power factor
(c) To improve the power factor, we need to add capacitance to the circuit. The value of capacitance required can be calculated using the formula:
Capacitance = (tan(θ1) - tan(θ2)) / (2πfVR)
Where θ1 is the initial power factor angle (cos^(-1)(0.7)),
θ2 is the desired power factor angle (cos^(-1)(0.95)),
f is the frequency of the AC supply, V is the voltage, and R is the load resistance.
Learn more about frequency here:
https://brainly.com/question/14316711
#SPJ11
FILL IN THE BLANK the ________ is a permanently-occupied outpost in outer space, and it is an important stepping stone for further space exploration.
The International Space Station (ISS) is a permanently-occupied outpost in outer space, and it is an important stepping stone for further space exploration.
The International Space Station (ISS) serves as a permanently-occupied outpost in outer space. It is a collaborative project involving multiple space agencies and serves as a crucial platform for scientific research, technological advancements, and international cooperation in space exploration. The ISS provides a unique environment for astronauts to live and work in microgravity conditions, conducting experiments across various fields such as biology, physics, astronomy, and human physiology. It also serves as a testbed for developing technologies and systems required for long-duration space missions, including those aimed at exploring the Moon, Mars, and beyond. The ISS has played a significant role in advancing our understanding of space, fostering international partnerships, and paving the way for future space exploration endeavors.
Learn more about International Space Station here:
https://brainly.com/question/13033832
#SPJ11
unpolarized light of intensity i0 passes through two sheets of ideal polarizing material. if the transmitted intensity is 0.30i0, what is the angle between the polarizer and the analyzer?
The angle between the polarizer and the analyzer is 39.2°.
The intensity of unpolarized light passing through a polarizing material is reduced by a factor of 1/2 since only one polarization direction is allowed to pass through. Thus, if the unpolarized light of intensity i0 passes through two polarizing materials, the intensity of transmitted light will be (1/2)*(1/2)*i0 = 0.25i0.
Since the transmitted intensity given in the problem is 0.30i0, it means that the second polarizing material is at an angle with respect to the first one. The intensity of transmitted light through two polarizing materials at an angle θ is given by I = (1/2)*i0*cos²θ.
Thus, 0.30i0 = (1/2)*i0*cos²θ, which implies that cos²θ = 0.6 or cosθ = √0.6. Taking the inverse cosine of both sides, we get θ = 39.2° (rounded to one decimal place).
Learn more about polarizer here:-
https://brainly.com/question/31428863
#SPJ11
Empty versus critical universe: a. For the above empty universe model, invert the formula for z(d) to derive an expression for distance as a function of redshift z. For this use the notation do(z), where the subscript "0" denotes the null value of 2m. b. If a distance measurement is accurate to 10 percent, at what minimum redshift Zo can one observationally distinguish the redshift versus distance of an empty universe from a strictly linear Hubble law d =cz/H, c. Using the above results from Exercise la, now derive an analogous distance ver- sus redshift formula dı(z) for the critical universe with 12m=1 (and Na=0). d. Again, if a distance measurement is accurate to 10 percent, at what minimum redshift z1 can one observationally distinguish the redshift versus distance of such a critical universe from a strictly linear Hubble law. e. Finally, again with a distance measurement accurate to 10 percent, at what minimum redshift Z10 can one observationally distinguish the redshift versus distance of a critical universe from an empty universe?
a. We can use the notation d₀(z) to represent the distance as a function of redshift:
[tex]do(z) = [(z + 1) / (z - 1)]^2[/tex]
b. We can solve this equation numerically to find the minimum redshift Z₀.
[tex][(z + 1) / (z - 1)]^2 = (1 ± 0.1) * cz/H[/tex]
c. In the critical universe, the redshift is zero for all distances. Therefore, we cannot derive a meaningful distance versus the redshift formula (d₁(z)) for the critical universe since the redshift is constant at zero.
d. There is no minimum redshift z₁ to distinguish the two cases.
e. We can solve this equation numerically to find the minimum redshift Z₁₀.
[tex][(Z10 + 1) / (Z10 - 1)]^2 = (1 ± 0.1) * cz/H[/tex]
What is redshift?a. To derive an expression for distance as a function of redshift in the empty universe model, we'll start with the inverted formula for redshift as a function of distance (z(d)) from Exercise 1a and solve for distance (d) as a function of redshift (z). Let's use the notation do(z), where the subscript "0" denotes the null value of 2m.
In the empty universe model, the formula for redshift as a function of distance is given by:
[tex]z(d) = [(2m)^(-1/2) - 1] / [(2m)^(-1/2) + 1][/tex]
To invert this formula and express distance as a function of redshift, we'll solve for d:
[tex]z = [(2m)^(-1/2) - 1] / [(2m)^(-1/2) + 1][/tex]
Rearranging the equation:
[tex][(2m)^(-1/2) - 1] = z * [(2m)^(-1/2) + 1][/tex]
Expanding both sides:
[tex](2m)^(-1/2) - 1 = z * (2m)^(-1/2) + z[/tex]
Isolating (2m)^(-1/2):
[tex](2m)^(-1/2) = (z - 1) / (z + 1)[/tex]
Taking the reciprocal of both sides:
[tex](2m)^(1/2) = (z + 1) / (z - 1)[/tex]
Squaring both sides:
[tex]2m = [(z + 1) / (z - 1)]^2[/tex]
Now, we can use the notation do(z) to represent the distance as a function of redshift:
[tex]do(z) = [(z + 1) / (z - 1)]^2[/tex]
b. If a distance measurement is accurate to 10 percent, we need to determine the minimum redshift Zo at which we can observationally distinguish the redshift versus distance of an empty universe from a strictly linear Hubble law (d = cz/H).
In the linear Hubble law, the relationship between distance (d) and redshift (z) is given by:
[tex]d = cz/H[/tex]
Let's assume our observed distance (do) is within 10 percent of the distance predicted by the linear Hubble law. Therefore, we can write:
[tex]do = (1 ± 0.1) * cz/H[/tex]
To distinguish between the empty universe model and the linear Hubble law, we need to find the redshift at which the distance differs by at least 10 percent. Let's substitute the expression for do(z) from part a into the equation:
[tex][(z + 1) / (z - 1)]^2 = (1 ± 0.1) * cz/H[/tex]
We can solve this equation numerically to find the minimum redshift Zo.
c. For the critical universe with 2m = 1 (and Na = 0), we'll derive the distance versus redshift formula (dı(z)) using the results from Exercise 1a.
In the critical universe model, the formula for redshift as a function of distance is given by:
[tex]z(d) = [(2m)^(-1/2) - 1] / [(2m)^(-1/2) + 1][/tex]
Substituting 2m = 1:
[tex]z(d) = [(1)^(-1/2) - 1] / [(1)^(-1/2) + 1][/tex]
Simplifying:
[tex]z(d) = 0[/tex]
In the critical universe, the redshift is zero for all distances. Therefore, we cannot derive a meaningful distance versus the redshift formula (dı(z)) for the critical universe since the redshift is constant at zero.
d. To observationally distinguish the redshift versus distance of a critical universe from a strictly linear Hubble law, we need to find the minimum redshift z1 at which the distance differs by at least 10 percent. However, since the redshift in the critical universe is always zero, there is no redshift at which the distance would differ from the linear Hubble law. Therefore, there is no minimum redshift z1 to distinguish the two cases.
e. To observationally distinguish the redshift versus distance of a critical universe from an empty universe with a 10 percent accuracy, we need to find the minimum redshift Z10.
Using the results from part a, the expression for distance in the empty universe (do(z)) is:
[tex]do(z) = [(z + 1) / (z - 1)]^2[/tex]
To distinguish between the critical universe (redshift always zero) and the empty universe, we need to find the redshift Z10 at which the distance differs by at least 10 percent. Let's substitute the expression for do(z) into the equation:
[tex][(Z10 + 1) / (Z10 - 1)]^2 = (1 ± 0.1) * cz/H[/tex]
We can solve this equation numerically to find the minimum redshift Z10.
Learn more about redshift
brainly.com/question/13494718
#SPJ11
In a circle with radius of 10 millimeters, find the area of a sector whose central angle is 102°. Use 3.14 for π a. 177.93 mm^2b. 88.97 mm^2 c. 314 mm^2 d. 355.87 mm^2
In a circle with a radius of 10 millimeters, the area of a sector whose central angle is 102° is approximately 88.97 mm^2 (option b).
1. Calculate the fraction of the circle represented by the sector: Divide the central angle (102°) by the total degrees in a circle (360°).
Fraction = (102°/360°)
2. Calculate the area of the entire circle using the formula A = πr^2, where A is the area, π is 3.14, and r is the radius (10 millimeters).
A = 3.14 * (10 mm)^2
3. Multiply the area of the entire circle by the fraction calculated in step 1 to find the area of the sector.
Area of sector = Fraction * A
Calculating the values:
1. Fraction = (102°/360°) = 0.2833
2. A = 3.14 * (10 mm)^2 = 3.14 * 100 mm^2 = 314 mm^2
3. Area of sector = 0.2833 * 314 mm^2 ≈ 88.97 mm^2
To know more about circle refer https://brainly.com/question/20489969
#SPJ11
A sturdy balloon with volume of 0.500 m ^3 is attached to a 2.50×10^2 kg iron weight and tossed overboard into a freshwater lake. The balloon is made of a light material of negligible mass and elasticity (though it can be compressed). The air in the balloon is initially at atmospheric pressure. The system fails to sink and there are no more weights, so a skin diver decides to drag it deep enough so that the balloon will remain submerged. (denisty of water =1000 kg/m^3) (a) Find the volume of the balloon at the point where the system will remain submerged, in equilibrium. (b) What is the balloon pressure at that point? Assume the temperature does not change with depth.
The volume of the balloon when it is submerged in the water and remains in equilibrium is 0.038 m^3. The pressure of the balloon at that point is 1.55 x 10^5 P
Since the system is in equilibrium, the weight of the balloon is equal to the buoyant force acting on it. The buoyant force is equal to the weight of the water displaced by the balloon. Hence, we can use Archimedes' principle to find the volume of the balloon when it is submerged and remains in equilibrium. We know that the density of water is 1000 kg/m^3 and the weight of the iron weight is 2.50 x 10^2 kg. Therefore, the weight of the water displaced by the iron weight is 2.50 x 10^2 kg x 9.81 m/s^2 = 2.4525 x 10^3 N. This is also equal to the weight of the balloon. Let the volume of the balloon when it is submerged be V. Then, the density of the balloon can be found using the mass and volume of the balloon. The mass of the balloon is negligible, so we can assume that the density of the balloon is the same as the density of the air inside it, which is approximately 1.29 kg/m^3. Therefore, the weight of the balloon is equal to the density of the balloon times the volume of the balloon times the acceleration due to gravity. Hence, we have 1.29 V x 9.81 = 2.4525 x 10^3. Solving for V, we get V = 0.038 m^3.
The pressure inside the balloon can be found using the ideal gas law, which relates the pressure, volume, and temperature of a gas. Since the temperature does not change with depth, we can assume that the temperature inside the balloon remains constant. Let P be the pressure inside the balloon at the point where it remains submerged. Then, the initial volume of the balloon is 0.500 m^3 and the initial pressure is atmospheric pressure, which is approximately 1.013 x 10^5 Pa. Using the ideal gas law, we have P x 0.500 = (1.013 x 10^5) x V. Substituting the value of V that we found earlier, we get P = 1.55 x 10^5 Pa. Hence, the pressure inside the balloon at the point where it remains submerged is 1.55 x 10^5 Pa.
Learn more about archimedes principle:
https://brainly.com/question/787619
#SPJ11
two forces of 692 and 423 newtons act on a point. the resultant force in 786 newtons. find the agle between the forces
Two forces of 692 and 423 newtons act on a point. the resultant force in 786 newtons: the angle between the forces is approximately 53.6 degrees.
What is forces?
Forces are physical quantities that cause an object to accelerate or deform. In physics, forces are described as interactions between two objects and are represented as vectors, which have both magnitude and direction.
To find the angle between the forces, we can use the law of cosines. According to the law of cosines, the square of the resultant force (786 N) is equal to the sum of the squares of the individual forces (692 N and 423 N) minus twice the product of the magnitudes of the forces multiplied by the cosine of the angle between them.
Mathematically, we can express this as:
786² = 692² + 423² - 2 × 692 × 423 × cosθ,
where θ represents the angle between the forces.
Simplifying this equation, we have:
θ = cos⁻¹((692² + 423² - 786²) / (2 × 692 × 423)).
Evaluating the expression using a calculator, we find that θ ≈ 53.6 degrees.
Therefore, the angle between the forces is approximately 53.6 degrees.
To know more about forces, refer here:
https://brainly.com/question/13820506#
#SPJ4
A study of car accidents and drivers who use cellular phones provided the following sample data. Cellular phone user Not cellular phone user Had accident 25 48 . Had no accident 280 412 a) What is the size of the table? (2) b) At a 0.01, test the claim that the occurrence of accidents is independent of the use of cellular phones. (15)
The size of the table is 4 cells. At a 0.01 significance level, we cannot reject the null hypothesis that the occurrence of accidents is independent of cellular phone use.
Step 1: Determine the size of the table. There are 2 rows (accident, no accident) and 2 columns (cell phone user, non-user), making a 2x2 table with 4 cells.
Step 2: Calculate the expected frequencies. The row and column totals are used to find the expected frequencies for each cell. For example, for cell phone users who had accidents, the expected frequency would be (25+280)*(25+48)/(25+48+280+412).
Step 3: Conduct a Chi-Square Test. Calculate the Chi-Square test statistic by comparing the observed and expected frequencies. Then, compare the test statistic to the critical value at a 0.01 significance level.
Step 4: Conclusion. Since the test statistic is less than the critical value, we fail to reject the null hypothesis, meaning the occurrence of accidents seems to be independent of cellular phone use.
Learn more about Chi-Square test here:
https://brainly.com/question/30696573
#SPJ11
Two large, flat, horizontally oriented plates are parallel to each other, a distance d apart. Half way between the two plates the electric field has magnitude E. If the separation of the plates is reduced to d2 what is the magnitude of the electric field half way between? a. 4E b. E c. 2E d. E/2
The magnitude of the electric field half way between two large, flat, horizontally oriented plates that are parallel to each other and a distance d apart is E. This is given in the question. However, if the separation of the plates is reduced to d2, we need to determine the new magnitude of the electric field half way between them. Option is b
To solve this problem, we can use the formula for the electric field between two parallel plates, which is E = σ/ε0, where σ is the surface charge density and ε0 is the permittivity of free space.When the plates are initially separated by a distance d, the surface charge density is spread over a larger area, resulting in a smaller magnitude of the electric field. However, when the plates are moved closer together to a separation of d2, the same amount of charge is now spread over a smaller area, resulting in a stronger electric field.
Therefore, the magnitude of the electric field half way between the plates when they are separated by a distance d2 is 2E, which is option c. This is because the surface charge density remains the same, but the area over which it is spread is reduced by a factor of 2. Hence, the electric field is doubled. Option is b.
For more such questions on electric field
https://brainly.com/question/19878202
#SPJ11
The magnitude of the electric field between two parallel plates is directly proportional to the distance between the plates.
Therefore, if the separation of the plates is reduced to d2, the electric field between them will increase. The new magnitude of the electric field half way between the plates can be calculated using the formula:
E2 = E x (d/d2)
where E is the original magnitude of the electric field and d and d2 are the original and new distances between the plates, respectively.
Substituting the given values, we get:
E2 = E x (d/d2) = E x (d/0.5d) = 2E
Therefore, the magnitude of the electric field half way between the plates is 2E. The answer is (c) 2E.
Calculating the magnitude of the electric field halfway between two large, flat, horizontally oriented plates when the separation is reduced to d2.
When the plates are a distance d apart, the electric field halfway between them has a magnitude E. If the separation is reduced to d2, the electric field will be inversely proportional to the separation. Since d2 is half of the original distance (d), the electric field magnitude will be twice as strong as before.
So, when the separation of the plates is reduced to d2, the magnitude of the electric field halfway between them will be 2E. The correct answer is c. 2E.
Visit here to learn more about electric field:
brainly.com/question/8971780
#SPJ11
he voltage across the inductor is vL =-(13.0V) sin((480rad/s)t]. Part A Derive an expression for the voltage VR across the resistor. Express your answer in terms of the variables L, R, Vų (amplitude of the voltage across the inductor), w, and t. VIR UR sin (wt - ) Lتا
the expression for the voltage VR across the resistor is VR = -(13.0V) * R/(L) cos((480rad/s)t) * t, where L is the inductance, R is the resistance, and t is the time
To derive an expression for the voltage VR across the resistor, we need to use Kirchhoff's voltage law, which states that the sum of the voltages around a closed loop in a circuit is zero. In this case, the loop includes the inductor and the resistor.
The voltage across the inductor is given as vL = -(13.0V) sin((480rad/s)t). We know that the voltage across a resistor is given by Ohm's law as VR = IR, where I is the current flowing through the resistor.
We can find the current flowing through the circuit by using the equation for the voltage across the inductor, which is vL = L(di/dt). We can rearrange this equation to find di/dt, which gives us the rate of change of the current. Thus, di/dt = (1/L) vL.
Substituting the given values, we get di/dt = -(13.0V)/(L) sin((480rad/s)t).
Now we can find the current flowing through the resistor as I = di/dt * t + I0, where I0 is the initial current when t=0. Since the current is alternating, we can assume that I0 = 0.
Therefore, I = -(13.0V)/(L) cos((480rad/s)t) * t.
Finally, we can find the voltage across the resistor as VR = IR * R. Substituting the expression for I, we get VR = -(13.0V) * R/(L) cos((480rad/s)t) * t. The amplitude of the voltage across the inductor is denoted by Vų, and the angular frequency is denoted by w.
To know more about voltage visit:
https://brainly.com/question/13521443
#SPJ11
You pull a simple pendulum of length 0.240 m to the side through an angle of 3.50 degrees and release it.a.) How much time does it take the pendulum bob to reach its highest speed?b.) How much time does it take if the pendulum is released at an angle of 1.75 degrees instead of 3.50 degrees?
The pendulum bob to reach its highest speed is 0.492 s.
A simple pendulum is a mass suspended from a fixed point by a string, which swings back and forth under the influence of gravity.
The time it takes for the pendulum to swing from one extreme to the other and back again (the period) depends on its length and the acceleration due to gravity. The longer the length, the slower the pendulum swings.
In this problem, we are given a simple pendulum of length 0.240 m that is pulled to the side through an angle of 3.50 degrees and released. To find the time it takes for the pendulum to reach its highest speed, we can use the formula for the period of a simple pendulum:
T = 2π√(L/g)
where T is the period, L is the length of the pendulum, and g is the acceleration due to gravity.
Using the given values, we can find that the period of the pendulum is 0.984 s. Since the time it takes for the pendulum to reach its highest speed is half of the period, the answer is 0.492 s.
If the pendulum is released at an angle of 1.75 degrees instead of 3.50 degrees, the length of the pendulum changes due to the trigonometry of the situation. Using the same formula, but with the new length, we can find the period to be 0.983 s. Therefore, the time it takes for the pendulum to reach its highest speed is 0.491 s, which is slightly shorter than the time for the larger angle.
Know more about pendulum here
https://brainly.com/question/29702798#
#SPJ11
Method for separating helium from natural gas (Fig. 18B.8). BSL problem 18B8 Pyrex glass is almost impermeable to all gases but helium. For example, the diffusivity of He through pyrex is about 25 times the diffusivity of H2 through pyrex hydrogen being the closest "competitor" in the diffusion process. This fact suggests that a method for separating helium from natural gas could be based on the relative diffusion rates through pyrex. Suppose a natural gas mixture is contained in a pyrex tube with dimensions shown in the figure. Obtain an expression for the rate at which helium will "leak" out of the tube, in terms the diffusivity of helium through pyrex, the interfacial concentrations of the helium in the pyrex, and the dimensions of the tube
The expression for the rate at which helium will leak out of the tube can be given as:
Rate of helium diffusion = (Diffusivity of helium through pyrex) × (Interfacial concentration of helium in pyrex) × (Area of pyrex tube) / (Thickness of pyrex tube)
To obtain the rate at which helium will "leak" out of the pyrex tube, we can use Fick's first law of diffusion. This law states that the rate of diffusion of a gas through a medium is proportional to the concentration gradient of that gas. In this case, the concentration gradient of helium in the pyrex tube will be dependent on the interfacial concentrations of helium in the pyrex and the dimensions of the tube.
Therefore, the expression for the rate at which helium will leak out of the tube can be given as:
Rate of helium diffusion = (Diffusivity of helium through pyrex) × (Interfacial concentration of helium in pyrex) × (Area of pyrex tube) / (Thickness of pyrex tube)
This expression shows that the rate of helium diffusion through pyrex will depend on the diffusivity of helium through pyrex, the interfacial concentration of helium in pyrex, and the dimensions of the pyrex tube. By using this expression, we can design a method for separating helium from natural gas based on the relative diffusion rates through pyrex.
Learn more about diffusion here:
https://brainly.com/question/31800291
#SPJ11
A toy duck is floating on the water. The average density of the duck is rhod = 860 kg/m3, while the density of water is rho = 1.0 x 103 kg/m3. The volume of the duck is Vd = 0.000105 m3. Express the weight of the duck, W, in terms of rhod and Vd. Calculate the numerical value of W in Newtons. Express the magnitude of the buoyant force, F, in terms of rho and the volume of water that the duck displaces, Vw.
The weight of the duck is 0.886 N and the buoyant force is 1.03 N.
We can calculate the weight of the duck using the formula:
W=m*g; where 'm' is the mass of the duck and 'g' is the acceleration due to gravity.
And the mass of the duck can be calculated by the formula:
[tex]m= rho_d * V_d[/tex]
where [tex]rho_d[/tex] is the density of the duck and [tex]V_d[/tex] is the volume of the duck.
Now after substituting the values into the formula, we get:
[tex]m= (860 kg/m^3) * (0.000105 m^3)[/tex]
m= 0.0903 kg.
Similarly, the weight of the duck will be:
W=m*g
[tex]W=(0.0903 kg) * (9.81 m/s^2)[/tex]
W = 0.886 N
Now the buoyant force (F) can be calculated using the formula:
F = rho*V*g; where 'rho' is the density of the water, 'V' is the volume of the water displaced by the duck, and 'g' is the acceleration due to gravity.
We can say that the volume of the water that is displaced by the duck is equal to its own volume so
[tex]V_d = 0.000105 m^3[/tex]
Substituting the values, we get:
[tex]F = (1.0 * 103 kg/m^3) * (0.000105 m^3) * (9.81 m/s^2)[/tex]
F = 1.03 N
Therefore, the weight of the duck is 0.886 N and the buoyant force is 1.03 N.
Learn more about buoyant force at:
https://brainly.com/question/28464280
#SPJ1
a rock of mass m, suspended on a string, is being raised, but it is slowing down with a constant acceleration of magnitude a, where a < g. what is the magnitude of the tension t in the string?
The magnitude of the tension in the string is T = m(g - a), where m is the rock's mass, g is the acceleration due to gravity, and a is the constant acceleration of the rock.
The tension (T) in the string holding the rock of mass (m) can be determined using Newton's second law of motion.
As the rock is being raised and slowing down with a constant acceleration (a) less than the acceleration due to gravity (g), it experiences two forces: gravitational force (mg) and tension force (T).
Since the rock is slowing down while being raised, the tension force must be less than the gravitational force. To find the net force acting on the rock, subtract the tension from the gravitational force:
F_net = mg - T.
According to Newton's second law, F_net = ma. Substitute the values to get:
ma = mg - T.
Now, solve for tension T:
T = mg - ma.
Since both terms have m, we can factor it out:
T = m(g - a).
Learn more about the tension at https://brainly.com/question/30070138
#SPJ11
A 8.0-cm radius disk with a rotational inertia of 0.12 kg ·m2 is free to rotate on a horizontal
axis. A string is fastened to the surface of the disk and a 10-kgmass hangs from the other end.
The mass is raised by using a crank to apply a 9.0-N·mtorque to the disk. The acceleration of
the mass is:
A. 0.50m/s2
B. 1.7m/s2
C. 6.2m/s2
D. 12m/s2
E. 20m/s2
The acceleration of the mass is: 1.7 [tex]m/s^2[/tex]. The correct option is (B).
To solve this problem, we can use the formula τ = Iα, where τ is the torque applied to the disk, I is the rotational inertia of the disk, and α is the angular acceleration of the disk.
We can also use the formula a = αr, where a is the linear acceleration of the mass and r is the radius of the disk.
Using the given values, we can first solve for the angular acceleration:
τ = Iα
9.0 N·m = 0.12 kg·[tex]m^2[/tex] α
α = 75 N·m / (0.12 kg·[tex]m^2[/tex])
α = 625 rad/[tex]s^2[/tex]
Then, we can solve for the linear acceleration:
a = αr
a = 625 rad/[tex]s^2[/tex] * 0.08 m
a = 50 [tex]m/s^2[/tex]
However, this is the acceleration of the disk, not the mass. To find the acceleration of the mass, we need to consider the force of gravity acting on it:
F = ma
10 kg * a = 98 N
a = 9.8 [tex]m/s^2[/tex]
Finally, we can calculate the acceleration of the mass as it is being raised: a = αr - g
a = 50 m/[tex]s^2[/tex] - 9.8 [tex]m/s^2[/tex]
a = 40.2 [tex]m/s^2[/tex]
Converting this to [tex]m/s^2[/tex], we get 1.7 [tex]m/s^2[/tex]. Therefore, the acceleration of the mass is 1.7 [tex]m/s^2[/tex].
To know more about "Angular acceleration" refer here:
https://brainly.com/question/30237820#
#SPJ11
Using the key terms, write a summary that describes the future of the Sun in terms of this "battle" between the pressure created by fusion in the Sun (either in the core or in a shell) and the force of gravity trying to squeeze it into a tiny sphere. Fusion converts mass to energy in the form of very high-energy light, known as gamma ray radiation. Where do the high temperatures in the core come from? What will the Sun's final composition be? Consider including the size of the Sun at each stage. If we were able to view it from afar, how much would we see it expand and shrink?
The high temperatures in the core of the sun come from immense gravitational force.
The Sun will expand to approximately 100 times its current size.
The Sun's final composition will be a cold, dense black dwarf, made up of carbon, oxygen.
The future of the Sun can be described as a continuous battle between the pressure created by fusion and the force of gravity. In the Sun's core, fusion occurs, converting hydrogen into helium and mass into energy in the form of gamma ray radiation. This fusion process creates immense pressure that counteracts the force of gravity trying to compress the Sun into a tiny sphere.
The high temperatures in the core, which enable fusion to occur, come from the immense gravitational force acting on the Sun's matter. As the Sun uses up its hydrogen fuel, it will enter different stages of its life cycle, expanding and shrinking in size.
Eventually, the Sun will exhaust its hydrogen fuel in the core and start burning hydrogen in a shell around the core. This will cause the Sun to expand into a red giant, becoming much larger than its current size. The outer layers will eventually be expelled, forming a planetary nebula.
As the core continues to contract under gravity, it will heat up and begin fusing helium into heavier elements, such as carbon and oxygen. Once the helium is exhausted, the core will no longer have sufficient pressure to counteract gravity, and the Sun will collapse into a white dwarf. Over time, the white dwarf will cool and become a black dwarf.
In summary, the Sun's life cycle involves a constant struggle between fusion pressure and gravitational force, which causes it to expand and contract through different stages.
The Sun's final composition will be a cold, dense black dwarf, made up of carbon, oxygen, and other heavier elements.
From afar, we would see the Sun expand to approximately 100 times its current size before shrinking back down to the size of a white dwarf.
To learn more about the Sun, visit:
https://brainly.com/question/28248963
#SPJ11
compute the power for the element (a). assume that va = -13 v and ia = 3 a . be sure to give the correct algebraic sign. Express your answer to two significant figures and include the appropriate units
The power for element (a) is -39 VA to two significant figures with the correct algebraic sign.
To compute the power for element (a), we can use the formula P = V * I, where P is power, V is voltage, and I is current.
Substituting the given values, we get:
P = (-13 V) * (3 A) = -39 W
Since the voltage is negative and the current is positive, the power is negative, indicating that the element is absorbing power rather than supplying it.
Expressing the answer to two significant figures and including the appropriate units, the power for element (a) is -39 W.
Learn more about element
brainly.com/question/13025901
#SPJ11